The invention relates to a process, as well as a system, for the calculation of the data relevant for the operation of the crane.
During its operation, a crane has a load torque limitation, which is intended to actively impede an excess load situation of the crane. An examination of the current bearing load against a permissible bearing load, which is determined in advance on the basis of stored values, usually occurs within the load torque limitation. Values specific to the crane and values stored in the crane, as well as order-specific values that specify the current equipment and environmental situation of the crane, or even normative specifications, for example, are thereby taken into consideration.
The computing capacity on a mobile working machine, like the memory storage units that already exist, must be constructed very sturdily, and also be constructed efficiently and be tested thoroughly in advance. The computing capacity and memory storage units are thus not to be compared with the values known from the area of home computing. The computation of the bearing load of a mobile crane and its boom systems, however, is a very computation-intensive task, which cannot be reasonably carried out during the service life of the crane by means of the computer resources available.
It is, therefore, a matter of the state of the art to store a bearing load table computed with external means and to refer back to the bearing load tables computed in advance during the operation of the crane. For that purpose, bearing load tables for all relevant combinations of the values specific to the crane and specific to the order are generally computed before beginning the operation of the crane and stored in the LMB [load torque limitation]. Because of the enormous quantity of data connected with that, it is not possible to compute bearing load tables corresponding to all conceivable combinations in advance. The best fitting bearing load table must thus be selected each time for scenarios not computed in advance. An interpolation onto the crane between two or more bearing load tables can also be avoided.
Efforts have already been made to carry out partial calculations on the crane and to optimize these. Non-computation-intensive calculations are also sometimes determined, however, with values for a permissible bearing load being computed in advance in the processing unit present on the crane and stored in the crane. The non-computation-intensive calculation of stability is thereby preferably carried out on the crane. The very expensive calculation of boom strength is computed in advance corresponding to the state of the art and stored retrievably on the crane by means of a memory storage unit.
It is true for all previous possibilities for solutions, however, that, because of the multiplicity of different parameters that are taken into consideration for a calculation of the bearing load tables, it is nearly impossible to make an individual bearing load table available for all different operating situations of the crane. The bearing load table used does not, consequently, form the specific operating conditions of the crane, so that inaccuracies in the determination of the permissible bearing load must be taken into account. For reasons of safety, a safety margin that takes these inaccuracies into account must thus be included for the load torque limitation. As the result of this, the bearing load that is actually possible cannot be completely utilized.